ในปัจจุบันทุกคนที่ใช้ COMPUTER มักจะมี Trump Drive สำหรับเก็บข้อมูลส่วนตัว ซึ่งในบาง trump drive นั้นจะมีโปรแกรม auto-run เพื่อว่าเมื่อเสียบ trump drive ไปแล้ว โปรแกรมจะได้ทำงานได้ทันที ซึ่งจริงๆแล้วตรงนี้เป็นประโยชน์ ทำให้การใช้งานได้สะดวก แต่ในขณะเดียวกัน ก็มีคนจำนวนหนึ่ง กลับใช้ auto-run นี้ ในการแพร่กระจาย virus ทั้งที่น่ารังเกลียด คือการให้โปรแกรม auto-run ทำการขโมย หรือ ลบ ข้อมูลในเครื่อง computer ที่เสียบ trump drive นั้นเข้า


ซึ่งจะได้ภาพ

วิธีที่จัดการปัญหานี้ แนะนำให้ disable auto-run ไปเลย ซึ่งน่าจะเป็นการดีกว่าที่ปล่อยให้ trump drive หรือ CD ที่มี auto-run ทำงานมาขโมยข้อมูลต่างๆของเรา
วิธีการ disable-autorun ใน window XP นั้นทำได้ง่ายมาก

1. เรียกโปรแกม gpedit.msc

2. Click ที่ Aminstator Templates/System/Trun off Autoplay

3. แก้ไขเป็น Eabled และ All drives

4. Click OK / Reboot

ให้ทดสอบง่ายๆ ด้วยการเสียบแผ่น CD ที่มีโปรแกรม autorun ต่างๆดู จะเห็นว่าโปรแกรมจะไม่ได้ขึ้นมาอัตโนมัติ เพียงเท่านี้ เครื่อง computer ของคุณก็ลดความเสี่ยงต่อการถูก Hack / Virus ได้

One of the FreeBSD technologies used by Firefox 3 is the new memory allocator, “jemalloc”, which was written by FreeBSD developer Jason Evans for the FreeBSD 7 operating system. jemalloc is a fast, efficient memory allocator with excellent performance on multiprocessor machines. Though already a part of the FreeBSD 7 operating system, the Mozilla project has chosen to also incorporate it directly inside the Firefox 3 browser to improve memory performance and reduce memory use on other operating systems with legacy memory allocators.

According to the blog of Firefox developer Stuart Parmenter, “Our automated tests on Windows Vista showed a 22% drop in memory usage when we turned jemalloc on.” Commenting on the Linux version of the browser, he wrote, “We saw a good performance increase and a drop in memory.”

Another FreeBSD technology used by Firefox is the “bsdiff” binary patch system written by Colin Percival as part of the FreeBSD Update mechanism for updating the FreeBSD operating system. By using bsdiff, Firefox is able to dramatically reduce the size of its software updates, meaning faster downloads for end users. In addition to being used by FreeBSD and Firefox, bsdiff is used by Apple to distribute updates to the OS X operating system.

The FreeBSD operating system is supporting Firefox in other ways, too. FreeBSD was integral in delivering Firefox software into the hands of users through its association with the Internet Systems Consortium (ISC), which operates one of the Mozilla project’s primary download mirrors, mozilla.isc.org.

ISC is a long-time supporter of the FreeBSD project, and FreeBSD 7 powers the mirror that withstood a sustained download rate of a gigabit per second, during peak download periods throughout Firefox’s world record breaking “Download Day.”

“ISC saw four times the normal volume of downloads from the mozilla.isc.org site during Download Day,” said Peter Losher, Hosted@ISC Programme manager. “As usual, FreeBSD proved to be a rock-solid platform enabling us to deliver content without incident.”

About the FreeBSD Project:

Building on a 30 year development history, the FreeBSD operating system is descended from the pioneering code upon which much of the Internet and modern computing was founded. It continues to be actively developed, with world-class stability, performance and modern features not available in other operating systems, even some of the best commercial ones.

FreeBSD technology can be found throughout the IT industry, providing key components of Apple’s OS X, network infrastructure from Juniper, Nokia, IronPort and other vendors, storage appliances from NetApp and Isilon, and even appearing from time to time in Microsoft Windows, among many other products.

The FreeBSD operating system is freely available under the BSD license, a business-friendly open source license that encourages code reuse and adoption within both open-source and proprietary products. Our mission is to provide world-class operating system code and technologies to all users for use in their own systems, regardless of their eventual disposition.

By choosing to build their products on top of FreeBSD source code, companies remain in control of deciding when and how their changes should be contributed back to the community. However, our developers are ready to work with companies and projects who make use of FreeBSD source code, and many companies have found that engaging with the open source community helps to reduce their integration and maintenance costs.

For more information about the FreeBSD operating system, please visit http://www.freebsd.org/, where the operating system is also available free for download or for purchase on CD or DVD through our partner organizations.

About The FreeBSD Foundation:

The FreeBSD Foundation is a 501(c)(3) non-profit organization dedicated to supporting the FreeBSD Project and community. The Foundation gratefully accepts donations from individuals and businesses, using them to fund and manage projects, sponsor FreeBSD events, Developer Summits and provide travel grants to FreeBSD developers. In addition, the Foundation represents the FreeBSD Project in executing contracts, license agreements, and other legal arrangements that require a recognized legal entity. The FreeBSD Foundation is entirely supported by donations. More information about The FreeBSD Foundation is available on the web at http://www.FreeBSDFoundation.org/.

public static string ComputeSHA1Hash(string fileName)
{
            return ComputeHash(fileName, new SHA1Managed());
}

public static string ComputeSHA256Hash(string fileName)
{
            return ComputeHash(fileName, new SHA256Managed());
}

public static string ComputeSHA384Hash(string fileName)
{
            return ComputeHash(fileName, new SHA384Managed());
}

public static string ComputeSHA512Hash(string fileName)
{
            return ComputeHash(fileName, new SHA512Managed());
}

public static string ComputeHash(string fileName, HashAlgorithm hashAlgorithm)
{
            FileStream stmcheck = File.OpenRead(fileName);
            try
            {
                        byte[] hash = hashAlgorithm.ComputeHash(stmcheck);
                        string computed = BitConverter.ToString(hash).Replace(“-”, “”);
                        return computed;
            }
            finally
            {
                        stmcheck.Close();
            }
}

public static bool VerifyHash(string fileName,
string hashAlgorithm,
string hashValue)
{
            string expectedHashString = “”;
            // Make sure that hashing algorithm name is specified.
            if (hashAlgorithm == null)
            {
                        hashAlgorithm = “”;
            }

            // Size of hash is based on the specified algorithm.
            switch (hashAlgorithm.ToUpper())
            {
                        case “SHA1″:
                                    // Compute a new hash string to compare.
                                    expectedHashString = ComputeSHA1Hash(fileName);
                        break;

                        case “SHA256″:
                                    // Compute a new hash string to compare.
                                    expectedHashString = ComputeSHA256Hash(fileName);
                        break;

                        case “SHA384″:
                                    // Compute a new hash string to compare.
                                    expectedHashString = ComputeSHA384Hash(fileName);
                        break;

                        case “SHA512″:
                                    // Compute a new hash string to compare.
                                    expectedHashString = ComputeSHA512Hash(fileName);
                        break;

                        default: // Must be MD5
                                    expectedHashString = ComputeMD5Hash(fileName);
                        break;
            }

            // If the computed hash matches the specified hash,
            // the plain text value must be correct.
            return (hashValue == expectedHashString);
}

System.IO provides all the necessary classes, methods, and properties for manipulating directories and files. Table 1 elaborates the main classes under this namespace.

Table 1—Classes under System.IO

Working with DirectoryInfo and FileInfo classes

The base class of DirectoryInfo and FileInfo is FileSystemInfo. This is an abstract class, meaning you can’t instantiate this class. But you can use the properties defined by this class. Table 2 elaborates its properties and methods.

Table 2—Members of FileSystemInfo class

The DirectoryInfo class provides methods for creating, moving, and deleting directories. To make use of the above properties, create an object of the DirectoryInfo class as shown in Listing 1:

Listing 1

DirectoryInfo dir1 = new DirectoryInfo(@"F:\WINNT");

You then can access the properties by using the object dir1, as shown in the code fragment in Listing 2:

Listing 2

Console.WriteLine("Full Name is : {0}", dir1.FullName);
Console.WriteLine("Attributes are : {0}",
                   dir1.Attributes.ToString());

You can also apply the values of FileAttributes enumeration. Its values are shown in Table 3.

Table 3—FileAttributes Enumeration Values

Working with Files under a Directory

Suppose that you want to list all BMP files under the f:\Pictures directory. You can write a code as shown in the code snippet given in Listing 3:

Listing 3

DirectoryInfo dir = new DirectoryInfo(@"F:\WINNT");
FileInfo[] bmpfiles = dir.GetFiles("*.bmp);
Console.WriteLine("Total number of bmp files", bmpfiles.Length);
Foreach( FileInfo f in bmpfiles)
{
  Console.WriteLine("Name is : {0}", f.Name);
  Console.WriteLine("Length of the file is : {0}", f.Length);
  Console.WriteLine("Creation time is : {0}", f.CreationTime);
  Console.WriteLine("Attributes of the file are : {0}",
                     f.Attributes.ToString());
}

Creating Subdirectories

You can easily create a subdirectory. Listing fragment 4 describes how to create a subdirectory called MySub under the Sub directory.

Listing 4

DirectoryInfo dir = new DirectoryInfo(@"F:\WINNT");
try
{
  dir.CreateSubdirectory("Sub");
  dir.CreateSubdirectory(@"Sub\MySub");
}
catch(IOException e)
{
  Console.WriteLine(e.Message);
}

Creating Files by Using the FileInfo Class

With the FileInfo class, you can create new files, access information about the files, delete, and move files. This class also provides methods for opening, reading from, and writing to a file. Listing 5 shows how to create a text file and access its information like its creation time, full name, and so forth.

Listing 5

FileInfo fi = new FileInfo(@"F:\Myprogram.txt");
FileStream fstr = fi.Create();
Console.WriteLine("Creation Time: {0}",f.CreationTime);
Console.WriteLine("Full Name: {0}",f.FullName);
Console.WriteLine("FileAttributes: {0}",f.Attributes.ToString());

//Way to delete Myprogram.txt file.

Console.WriteLine("Press any key to delete the file");
Console.Read();
fstr.Close();
fi.Delete();

Understanding the Open() Method

The FileInfo class defines a method named Open() with which you can create files by applying the values of the FileMode and FileAccess enumerations. The code snippet in Listing 6 describes its usage:

Listing 6

FileInfo f = new FileInfo("c:\myfile.txt");
FileStream s = f.Open(FileMode.OpenorWrite, FileAccess.Read);

You then can read from and write to a file by using the object ‘s’. In the overloaded Open() method, permission is given only for reading from a file. If you want to write to a file, you have to apply the ReadWrite value of FileAccess enumeration. Tables 4 and 5 describe the values of the FileMode and FileAccess enumerations.

Table 4—FileMode Enumeration values

Table 5—FileAccess Enumeration values

Writing to a Text File by Using the StreamWriter Class

You can easily write texts or other information to a file by using the CreateText() method of the FileInfo class. However, you have to obtain a valid StreamWriter. It’s this StreamWriter reference that provides the required functionalities for writing to a file. To illustrate, Listing 7 writes a series of texts to the Mytext.txt file.

Listing 7

FileInfo f = new FileInfo("Mytext.txt")
StreamWriter w = f.CreateText();
w.WriteLine("This is from");
w.WriteLine("Chapter 6");
w.WriteLine("Of C# Module");
w.Write(w.NewLine);
w.WriteLine("Thanks for your time");
w.Close();

Reading from a Text File

You can read from a Text file by using the StreamReader class. For this, you have to specify the file name using the static OpenText() method of the File class. Listing 8 reads the contents that we have written in Listing 7:

Listing 8

Console.WriteLine("Reading the contents from the file");
StreamReader s = File.OpenText("Mytext.txt");
string read = null;
while ((read = s.ReadLine()) != null)
{
  Console.WriteLine(read);
}
s.Close();

About the Author

Anand Narayanaswamy works as a freelance Web/Software developer and technical writer. He runs and maintains learnxpress.com, and provides free technical support to users. His areas of interest include Web development, Software development using Visual Basic, and in the design and preparation of courseware, technical articles, and tutorials.

string extension=””;

char []arr=fileName.ToCharArray();

int index=0;

for(int i=0;i<arr.Length;i++)

{

if(arr[i]==’.’)

{

index=i;

}

}

for(int x=index+1;x<arr.Length;x++)

{

extension=extension+arr[x];

}

return extension;

}

public static void ProcessDir(string sourceDir, int recursionLvl)
{
if (recursionLvl<=HowDeepToScan)
{
// Process the list of files found in the directory.

string [] fileEntries = Directory.GetFiles(sourceDir);
foreach(string fileName in fileEntries)
{
// do something with fileName
Console.WriteLine(fileName);
}

// Recurse into subdirectories of this directory.
string [] subdirEntries = Directory.GetDirectories(sourceDir);
foreach(string subdir in subdirEntries)
// Do not iterate through reparse points
if ((File.GetAttributes(subdir) & FileAttributes.ReparsePoint) != FileAttributes.ReparsePoint)
{
ProcessDir(subdir,recursionLvl+1);
}
}
}

Source: weblogs.asp.net

// Function: Get specified files (fileType) form sub-directory (sourceDir)
// Return: void
public void getJPGFromSubDir(string sourceDir, string fileType)
{
string[] dirEntries = Directory.GetDirectories(sourceDir);
string fileName, filePath, fullFileName;

foreach (string subDir in dirEntries)
{
DirectoryInfo dir = new DirectoryInfo(subDir);
FileInfo[] imgFiles = dir.GetFiles(fileType);

foreach (FileInfo imgFile in imgFiles)
{
fileName = imgFile.Name;
filePath = imgFile.DirectoryName;
fullFileName = filePath + “\\” + fileName;);
}
}
}